(a) Field of the Invention
The present invention relates to a curtain blind power conversion device with reverse brake effect, and more particularly to the conversion device that provides a power terminal that achieves torsional conversion and the reverse brake effect for horizontal or vertical curtain blinds. The conversion device primarily utilizes two annular gears, wherein number of teeth and module of the two annular gears are unequal. The two annular gears synchronously engage with a single planetary gear set, and utilization is made of the unequal circular pitch and module of the two annular gears to produce an angular speed difference, thereby realizing a deceleration output motive force, and with the planetary gear set being subject to a fixed restriction of a first annular gear, the reverse brake effect is thereby achieved.
(b) Description of the Prior Art
Primary application of the present invention is in usage as a reverse brake for curtain blinds. Referring to FIG. 1, which shows a conventional curtain blind 1, wherein, in order to achieve object of the reverse brake, the curtain blind 1 is configured with a drive unit 12 having an energy potential.
The drive unit 12 is actuated by means of a worm gear 124 (see FIG. 2) through a worm 125 utilizing a relatively high slip ratio of inclined screw teeth. Wherein the worm 125 is driven by means of a sprocket wheel 126 through manual operation of a beaded chain 121, whereby turning power generated is same as that obtained by means of an electric motor 20 substituting for the sprocket wheel 126.
The drive unit 12 synchronously drives two take-up tubes 123 through an angle-shaped transmission rod 122 (see FIG. 1). The take-up tubes 123 actuate slats 14 configured lower to the take-up tubes 123 by means of pull wires 141, thereby taking up and letting down the slats 14 therewith. Anti-glare angle of the horizontal slats 14 is regulated by adjustment of angle of elevation through tilt leaves 13 actuating ladder cords 142.
However, because the aforementioned curtain blind 1 is fitted on a window, force of wind blowing from outside causes the curtain blind 1 to move, and thereby results in the slats 14 sliding down. After the slats 14 have slid down, motive force of the wind consequently effectuates a reverse direction transmission to the drive unit 12 through the take-up tubes 123, and indirectly through the transmission rod 122, subsequently the drive unit 12 is subject to a relatively large external force feedback, which produces slippage thereat.
FIG. 2 depicts an improved brake configuration presently employed in curtain blinds, and because the worm gear 124 is positioned within a top horizontal rail 11, dimensions of the brake configuration is small in proportion, moreover, force is transmitted to a single tooth of the worm gear 124 through engagement with the worm 125, which thus forms a tooth surface pressure on a large single spot, subsequently the worm gear 124 or spiral teeth of the worm 125 are easily damaged, causing dislodging of the gears to occur, and thereby object of locking is lost.
Furthermore, the aforementioned drive unit 12, in similar fashion, can actuate taking up and letting down of cloth curtains, and similarly, because of effect of the force of wind pressure and own weight of the cloth curtains, the cloth curtains also require the drive unit 12 to provide an effective reverse brake.
Referring to FIG. 2A, which shows another horizontal type curtain blind having a traditional design primarily embodying a lift-drop cord 140 and a slat tilt rod 120, wherewith the slats 14 are taken up or let down, and angle of incident light is adjusted. Basic configuration comprises the top horizontal rail 11 and the horizontal slats 14 connected lower thereof. Adjustment to the slats 14 is carried out by pull operating on the lift-drop cord 140, thereby achieving raising and taking up of the slats 14 or letting down and unfolding of the slats 14. Upon unfolding of the slats 14, the slat tilt rod 120 is employed to regulate the angle of incidence the slats 14 make with incoming light; moreover, the slat tilt rod 120 effectuates linkage with the worm 125 thereof. Through the worm 125 rotatedly engaging with the worm gear 124, the worm gear is thereby enabled to outwardly actuate the transmission rod 122, whereupon regulating angle of incident light for the slats 14 can thereby be realized. Furthermore, utilizing the worm 125 engaging with the worm gear 124 can achieve an external force that effectuates an opposing brake effect.
Because the horizontal type slats 14 are generally fitted at a maximum elevation of approximately 30 feet. Because, firstly, dimensions of packaging is restrictive, and secondly, if the slat tilt rod 120 is utilized to regulate angle of incoming light, then length of the slat tilt rod 120 must also be close on 30 feet in length, thus the long slat tilt rod 120 is unsuitable for usage. Hence, a sprocket drive method is adopted in replacement of the slat tilt rod 120.
Referring to FIG. 2B, which shows the sprocket drive method, which traditionally operates in coordination with satellite gears to enlarge torsional force and effectuate a brake configuration. The sprocket drive is primarily configured for the beaded chain 121 to actuate the sprocket wheel 126, and the sprocket wheel 126 actuates a conversion drive in a direction of the transmission rod 122 through a planetary gear set 18. The planetary gear set 18 is subject to a motive power from the sprocket wheel 126 linkage to a sun gear 181. Satellite gears 182 of the outer meshing ring are also subjected to corresponding meshing with a fixed annular gear, thereby enabling an attached carrier plate 180 to corotate. The carrier plate 180 externally connects to a shaft 190, and after the shaft 190 is distanced from a brake spring 192, linkage actuation of an output shaft 191 is effectuated. The output shaft 191 is externally linked to the transmission rod 122, and the brake spring 192 utilizes space between an external surface of the shaft 190 and the output shaft 191 to implement operation of radial opening or internal shrinkage, thereby if a transmission force is transmitted to the axle 190, the output shaft 191 will be subject to effect of the brake spring 192, and a constraint reacting force is generated thereat, thus achieving object of stopping reverse movement.
The principle of the constraint reacting force is such that one end of the brake spring 192 is peripherally fixed, thereby enabling diameter of the brake spring 192 to be variated through an axial torsion, for instance, when the diameter of the brake spring 192 is reduced, the constraint reacting force effect is thereupon generated. Design of the brake spring 192 is that of a mechanical design of a general brake spring for a curtain rail, and thus is not described in further detail herein.
Referring to configuration of FIG. 2B, the sprocket drive depicted applies a similar related drive structure as shown in FIG. 1, whereby the single beaded chain 121 achieves letting down and opening of the slats 14 and regulation of the angle the slats 14 make with irradiating light.
Although utilizing the beaded chain 121 enables achieving the various aforementioned functions, wherein the brake effect utilizes the constraint of reaction force or letting down operation or opening operation of the brake spring 192. However, upon the constraint reaction force and circumferential surface of the shaft 190 surpassing a critical limit, slippage still occurs and thus loss of locking functionality thereof.
Referring to FIG. 3, which shows a conventional design for a vertical curtain blind, wherein the drive unit 12 is configured in the top rail 11, and vertical slats 14 are connected to hanging shafts 15 configured below the top rail 11. The drive unit 12 is similarly actuated through an external force by means of manual operation of an operating cord 16.
Referring to FIG. 4, which shows an umbrella gear set 17 connected to one of the hanging shafts 15, below which is connected the slats 14. The umbrella gear set 17 is subject to horizontal actuation from the angle-shaped transmission rod 171, and whereby the transmission rod 171 is subject to actuation from the drive unit 12.
Utilizing actuation of the drive unit 12 thereby enables the umbrella gear set 17 to transfer drive to the hanging shafts 15, which thereon connectively actuate the slats 14, and thus realizes regulating angle of incident light hitting the slats thereof. However, surface pressure from force of natural wind effectuates producing a twisting phenomenon on the slats 14, which thereby blows the slats 14 into disorder, and thus the originally appropriately angled slats 14 become disorientated. Hence, a requirement for a braking method fitted on the drive unit 12 is necessary to effectively brake the angle-shaped transmission rod 171.
In order to prevent the transmission rod 171 from being subject to a reverse force from the hanging shafts 15, which is thereby indirectly transmitted to the drive unit 12, configuration of the drive unit 12 generally follows a structural principle depicted in FIG. 2, whereby a worm and a worm gear are utilized to achieve the brake effect. However, teeth of the worm and the worm gear are similarly subject to possibility of easily being damaged.
Recently, the brake effect utilizes a configuration embodying a magnetic-type mechanical control switch or other automatic devices having electrical components. However, electrical power is necessary in order to utilize such devices, and, moreover, configuration comprises complicated components.